Louvers mounted in rotatable barrel mounts and the like are the most common form of air control outlets utilized in automobiles (and also in homes and the like). There are certain well known limitations in the use of louvers in that they form an impedance causing a loss in air flow which increases as the louverse are turned transverse to the direction of flow. Moreover, when a louver is at an extreme right or left position in an automobile, as on the passenger side and adjacent the door, luvers can not be utilized to effectively direct air from that particular outlet towards the driver side when desired. As shown in FIG. 10, a conventional multi-louver element is commonly controlled by a lever (not shown) so that all of the louver elements are commonly moved by the linkage system. As the louvers are gradually moved in a direction to direct more flow of the air, the louvers also shut down the flow of air. Even when the louver is in a barrel mount and rotated on its axis, the rotation of the element in its barrel mount in effect begins to shut down air as the portions of the barrel mounting structure intercede into the flow path.
U.S. Pat. No. 2,812,980 and Canadian Pat. No. 493,723 disclose jet deflecting devices and processes in which an obstacle intrudes into the main flow path in association with a downstream rounded shaping of a bounding wall surface to enhance the deflection. A hybrid solenoid driven fluidic element and louvers is disclosed in Izumi et al. U.S. Pat. No. 4,407,186 and in Kakei U.S. Pat. No. 3,745,906 various fluidic and electromechanical deflection devices are used to oscillate defrost air in automobiles.
The basic object of the present invention is to provide an improved air distribution system, particularly for use in automobiles. A further object of the invention is to provide an improved air distribution system which has less impedance and hence is more efficient in distribution of air, and a control system in which the control does not add any significant impedance to the air flow and hence is more efficient. A further object of the invention is to provide relatively low impedance air flow distribution control system which is relatively shallow or short in design so that it does not protrude into the air flow channel or into the space of an automobile, for example. And in which the air flow can be deflected in four directions or left undeflected.
In accordance with the invention, an air outlet is formed in a duct, for example. In a preferred embodiment, a short diverging wall is formed adjacent the air flow outlet and a second wall forms an air flow passage which is parallel to the main flow and for purposes of description has an upstream end which is coupled to the air flow from the duct and a downstream end which directs air in a direction substantially parallel to the short diverging wall. The term "short" is intended to mean a wall which, in relation to the air flow, has no significant coanda effects. By controlling the inlet end of the air flow passage to block or unblock same, the main air flow stream through the outlet is controlled so as to move towards and away from the short parallel wall. The short parallel wall is of insufficient length for wall attachment purposes. While the short wall is preferrably curved, it can obviously be straight. The outlet, which preferrably is rectangular or square, provides five control directions, up, down, left, right, and straight ahead or any combination of adjacent directions. By a flap element or one movable short wall, it can be moved into the air stream so as to enhance the sweep angle. Alternatively, fixed louvers can be added parallel to the short walls so as to cause a greater sweep angle.
In a further aspect of the invention, the control element can be an intruder plate which intrudes a relatively short distance into an outlet at the terminus of a duct.